The rapid miniaturization in electronic devices, particularly their manufacture and assembly, has transformed the medical industry. In particular, handling and testing of cells and other components within body fluids has moved beyond the conventional test tube to other devices, such as biochips. A biochip, sometimes called a lab-on-a-chip, refers to the placement of testing of biologic materials on a miniature electronic device capable of electrically and/or chemically interacting with the biologic materials.
Considerable efforts have been made in the biochip environment to apply electric fields to manipulate cells, including their movement, separation, property determination, etc. Despite numerous attempts at cell manipulation with electric fields, the ability to manipulate cells is still limited by different characteristics of the cells, such as cell size, cell aggregation, cell polarizability, etc. For example, sorting cells into different groups is challenged by the great variety of sizes, shapes, polarizability, relative volumes of cells within a fluid, etc. Cell sorting is also affected by the characteristics of the fluid in which the cells are suspended during manipulation. Impeding sorting of the cells on the biochip, in turn, hampers the ability to perform other functions with the cells (e.g., collection, isolation, testing, etc.) on the biochip.
For these reasons, among others, widespread use of biochip devices has been limited.